Most Helpful Guy

As long as those people don't know him or you haven't been video taped or pictures taken while doing so AND your sense of 'morality' can handle it, I'd say keep it to yourself. Especially since one can never be sure how the other person may react and also that since he's your ex and you guys are planning on getting back.

What Girls Said 5

My best guy friend went to get back with his ex and she told him she'd slept with a guy in the mean time and he refused to get back with her...she had every right as they were broken up and he slept around too but he always said that he couldn't go back out with her KNOWING about it and he'd rather it be left unsaid

I would probably avoid telling him. I don't know your situation or why you two broke up to begin with, but no one likes to find out that the person they're interested has been sleeping with other people.